Fouling Mechanisms and Antifouling Technology

The formation of fouling during dairy processing as well as most other food products leads in most cases to the formation of an intertwined mineral and protein-based networks. The process is kinetically controlled and strongly dependent on process conditions. The deposition process is a balance between the attachment of the different components to the surface, their surfaces interactions and bulk interactions. In fact, chemical interactions and aggregation in bulk can make the component less sticky. Any cleaning process must take into account that in order to remove fouling, you need to remove both the protein and mineral network.

This talk will give an overview of the different fouling types that heat exchangers are subjected to. It will start by describing fouling and its consequences, followed by a description of the different types of fouling, the applications where it is encountered, how to prevent it, and what factors play a role in each of the different types. The last part of the talk will deal with different strategies for heat exchanger cleaning. In the past years, Alfa Laval has been working with different coatings for fouling reduction in heat exchangers and some results in scaling applications will be presented briefly.

In this presentation, the various coating types available (commercially and in research) for combatting biofouling on ship hulls and other underwater structures are reviewed. The working mechanisms of the coatings and the advantages and disadvantages of the product types are discussed. Finally, we will take a look at the test methods involved in research and development, including field studies.

It is important to use hygienic design as much as possible in the construction of food industry equipment, as it enables efficient and fast cleaning. In this talk, Annette Baltzer Larsen will present the different elements in hygienic design such as materials, joints, drainablity, etc. The efficiency of cleaning procedures can be monitored by analyzing the rinse water, however it is important that the rinse water is coming from everywhere in the closed equipment (pipes, valves, tanks, etc.). Otherwise it is not possible to use the rinse water as an indicator for the cleanability of the equipment. Results from a case study using rinse water for evaluating the efficiency of the cleaning will be showed.

Fouling of heat exchangers in the chemical industry, oil & gas industry, power plants, etc. results in significant loss of performance. This leads to production stops for cleaning and increased operating costs. Alfa Laval has been working on mitigating fouling by altering the properties of the metal surface with coatings. The coating has resulted in a significant improvement of the gasketed plate heat exchanger performance as well as less downtime for cleaning. Savings in energy, water, cleaning chemicals, etc. all contribute to a more sustainable and environmentally friendly operation.

This talk will present a new type of anti-fouling coatings which eliminate the attachment of unwanted species on the surfaces of heat exchangers. These coatings enable the heat exchangers to work at highest possible efficiency at all times. During the presentation some of the achievements and possible energy and cost savings will be presented, e.g. coatings installed in district heating units with sensors to track the efficiency.

Fouling has several disadvantages for technical systems, one of the most serious being microbially influenced corrosion, commonly known as MIC. This presentation will show participants the corrosion risk connected with fouling and MIC and make them able to identify possible risk in their own systems. Matthias Graff will give an overview of micro-organisms that can cause corrosion. The term “biofilm” will be explained as well as the limitations for microbial life, i.e. formation of biofilm. Last but not least, several MIC case studies will be presented.